patch 9.1.1429: dragging outside the tabpanel changes tabpagenr

Problem:  dragging outside the tabpanel changes tabpagenr (char101)
Solution: set in_tab_line and in_tabpanel variables (Hirohito Higashi)

fixes: #17385
closes: #17431

Signed-off-by: Hirohito Higashi <h.east.727@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/mouse.c b/src/mouse.c
index 0d05e64..dcb6cbe 100644
--- a/src/mouse.c
+++ b/src/mouse.c
@@ -337,7 +337,13 @@
 
     // Ignore drag and release events if we didn't get a click.
     if (is_click)
+    {
 	got_click = TRUE;
+	in_tab_line = FALSE;
+#if defined(FEAT_TABPANEL)
+	in_tabpanel = FALSE;
+#endif
+    }
     else
     {
 	if (!got_click)			// didn't get click, ignore